Time Travel: A Writer's Guide to the Real Science of Plausible Time Travel

CHAPTER 5 Time as the Fourth Dimension

CHAPTER 5 Time as the Fourth Dimension The shadow by my finger cast Divides thefuture from the past: Before it, sleeps the unborn hour, In darkness, and beyond thy power: Behind its unreturning line, The vanished hour, no longer thine: One hour alone is in thy hands, The now on which the shadow stands. "The Sun-Dial at Wells College" by Henry Van Dyke, 1904. Time as the fourth dimensionofspace-time, (rather than thatdimension being spatial in nature) is the current idea today. As with the spatial interpretation, the time view is an old one, which can be traced back to at least the eighteenth century. There is, in fact, a famous passage dating to 1751, in the writings ofthe French mathematician Jean le Rond D'Alembert (1717-1783), that showsjust how old such speculations are: "I have said [that it is] not possible to imagine more than three dimensions.Aclever acquaintanceofmine 74 Time Travel believes, however, that duration could be regarded as a fourth dimension ; that idea can be contested, but it seems to me that it has some merit, if only that of novelty." It wasn't until a curious letter appeared in Nature during 1885, however, that the concept oftime as the fourth dimensionwas mentioned seriously in an English-language scientific journal. The author , mysteriously signing himself only as "S.", began by writing, "What is the fourth dimension? . . . I [propose] to consider Time as a fourth dimension. . . . Since this fourth dimension cannot be introduced into space, as commonly understood, we require a new kind of space for its existence, which we may call time-space." Who was this prophetic writer? Nobodyknows. The idea of time as the fourth dimension entered the popular mind ten years later, around 1894-1895, with the first ofH.G.Wells's so-called scientificromances, The Time Machine.Twenty years after this pioneer use of time in literature, science fiction writers took the idea as the basis for one of their most popular subgenres. For example, Murray Leinster was quick to capitalize on time as the fourth dimension; his very first published story, "The Runaway Skyscraper" (which appeared in a 1919 issue of Argosy magazine), tells the incredible tale ofhow a Manhattan skyscraper and its 2,000 occupants' trip several thousand years backward in time when the building's foundation slips (in some unexplained way) along the fourth dimension. The scientific sophistication of the story is primitive, with just one ofthe logical flaws being a vivid description ofthe time travelers living normal, forward-in-time lives even as their wristwatches run backward. Indeed, when Hugo Gernsback reprinted the tale in one of the early issues of Amazing Stories, a reader complained about this very point. Gernsback felt compelled to defend the story in his November 1926 editorial "Plausibility in Scientifiction" (see the opening to chapter one), but he could muster only a weak rebuttal based on an author's right to "poetic license." Perhaps in 1926, but today such a slip would bring hoots of laughter down on a writer's head. Time as the Fourth Dimension 75 Using an interesting dual interpretation of the fourth dimension is Arthur C. Clarke's "Technical Error," the story of an electrical engineer who is caught in the middle of an enormous electromagnetic field surge produced by a short circuit in a power plant. As a physicist later explains to the utility's shaken board of directors: "It now appears that the unheard-of current, amounting to millionsof amperes . . . must have produced a certain extension into four dimensions . . . I have been making some calculations and have been able to satisfy myself that a 'hyperspace' about ten feet on a side was, in fact, generated: a matter ofsome ten thousand quartic— not cubic!—feet. Nelson was occupying that space. The sudden collapse ofthe field [when the overload breakers finally cut the circuit] caused the rotation of the space." Being rotated through four-dimensional space has inverted the unlucky Nelson (recall Alice and her looking-glass milk from the last chapter) and, to bring him back to normal, he must be flipped again. The physicist brushes aside a question about the fourth dimension as time, asserting the whole issue is simply one of space. Poor Nelson is again subjected to a stupendous power overload— only now he disappears. Too late, the physicist realizes that the fourth dimension is (in this story) both space and time. Nelson...